PROJECT SUMMARY/ABSTRACT This mentored patient-oriented research career development award (K23) will enable Dr. Roberts to achieve his long-term career goal of becoming an independent clinical researcher working to develop pharmacotherapies for alcohol use disorder (AUD). This proposal outlines a 5-year training plan that supports a research program focused on developing a mobile biosensor platform for tracking medication effects on alcohol reactivity in ambulating outpatients. Training domains include 1) mobile biosensor assessment of alcohol use, 2) management and analysis of biosensor data, and 3) AUD pharmacotherapy development research. The training plan includes a strategic combination of mentor-led trainings; coursework in mobile health sensing, data science, statistics, bioethics, clinical research methods, and grant writing; attendance at relevant conferences and workshops; and collaboration with investigators conducting research in AUD pharmacotherapy development. The candidate will complete these training activities while completing a research program aimed at developing a mobile biosensor platform that can passively track alcohol consumption and deliver conditional assessments at key points during drinking episodes. In these preliminary studies, heavy drinkers with AUD will wear the mobile biosensors and receive alcohol in the laboratory. In Experiment 1, participants will receive two fixed doses of alcohol while wearing the biosensors and responding to prompted assessments. Goals of this experiment will be to 1) refine the machine-learning derived detection algorithms that will identify key points during drinking episodes and 2) evaluate the user experience and feasibility of delivering prompted assessments on a smartphone during drinking episodes. Experiment 2 will test the detection algorithms in a separate sample of freely behaving participants engaged in self-paced alcohol drinking. Results of these studies will serve as pilot data to support an R-mechanism application to develop a formal paradigm using the biosensor platform to track medication effects of alcohol use and reactivity in ambulating outpatients. Dr. Roberts has assembled an mentorship committee of leaders in the field. Dr. McKee (primary mentor) is a Professor of Psychiatry at the Yale University. She applies innovative laboratory paradigms to AUD pharmacotherapy development research, and she has several lines of research using mobile health biosensors to track substance use behavior. Dr. Ramchandani (primary co-mentor) is a clinical investigator and Chief of the Human Psychopharmacology Section at the NIAAA intramural research program. He will lead Dr. Roberts's training in alcohol pharmacokinetics. Drs. Gueorguieva, Petrakis, and Gerstein will serve as secondary mentors and contribute to Dr. Roberts's training in longitudinal data analysis, AUD pharmacotherapy clinical trials, and machine learning and data science, respectively. Drs. Miranda and Barnett will serve as external advisers and support Dr. Roberts's training in ambulatory assessment in the context of medication development research and transdermal alcohol detection, respectively.